In magnetic resonance imaging (MRI), continuous table movement MRI enables fast imaging at isocenter for improved image quality that maintains continuity through patient support table movement direction and extends imaging field of view. Aspects affecting MRI imaging include (i) proximity to magnet isocenter (the most homogenous imaging region) and (ii) shimming of a main magnetic field to maximize field homogeneity and resultant image quality. Image acquisition in known systems is typically conducted by use of a static patient support table or by continuous table movement at constant table velocity throughout image acquisition. A static patient table without table movement during acquisition is common where images are acquired in a relatively localized region. For image scans involving large imaging regions (whole body, peripheral extremities, spine, for example), a table is moved between scans (while no data is acquired) followed by shimming at the new table position before image acquisition is resumed. Limitations of the known method include limited FOV (i.e., (Field of View—imaged anatomical area) for a given table position, potential image degradation at the edges of the FOV for image regions farther from isocenter, and discontinuities at the edges of image regions that are combined for viewing and diagnosis. Furthermore, performing needed separate magnetic field shimming operations at each table position is time consuming.
The use of continuous table movement during imaging allows for constant imaging near isocenter resulting in image quality improvement. Furthermore, shimming is more efficient and hence less time consuming. Additionally, continuous table movement acquisition provides image quality continuity throughout an extended FOV because separate scans at different static table positions are not needed. However, a single table velocity might not be optimal for different regions of the imaging FOV as anatomy and physiology can vary throughout the body. One known system described by Kruger G, et al. in a paper entitled “A dual-velocity acquisition method for continuously-moving-table contrast-enhanced MRA”, Proc ISMRM 2004, p. 233, utilizes a dual velocity approach to account for reduced flow in peripheral regions for contrast enhanced magnetic resonance angiography. This method utilizes a higher table velocity during data acquisition in the torso and reduced table velocity as the FOV reaches the knees. Another known system described by Aldefeld B, Boernert P, Kuepp J, et al. in a patent Application entitled “MRI of a continuously moving object involving motion compensation, US2009/0177076A1, Jul. 9, 2009, detects patient motion (including respiratory or cardiac gating variability) to modify table velocity during continuous table movement MRI. A system according to invention principles addresses the deficiencies and problems of these and other known systems.